Auto gain link closed-loop feedback control method in self-adapting focusing and leveling sensor system

Abstract

The invention discloses a self-adapting focusing and leveling sensor system and an application method thereof. The system is characterized in that a light spot mask is also provided with an light hole which generates a forecasting light spot positioned outside an exposure slit, by the use of the generated forecasting light spot outside the exposure slit, the self-adapting focusing and leveling system is capable of realizing the self-adaptation to technology, judging by self the confidence of the measurement data of a measuring point thereof, and carrying out feedback control on a light intensity or a gain link. The invention has the advantages of largely improving the availability of the self-adapting focusing and leveling sensor system, the production efficiency and the rate of finished products, reducing the workload of the technological experiments and the use cost, and improving the measurement performance of the focusing and the leveling as well as the working performance of a workpiece table, thus finally improving the working performance of a mask aligner and lowering the use cost and the use difficulty of the mask aligner.

Description

[0001] The present invention is a divisional application of the application number CN200610118480.7 "Adaptive Focusing and Leveling Sensor System and Application Method", and the filing date of the original application was November 17, 2006. technical field [0002] The invention belongs to the field of focusing and leveling sensors of projection lithography machines, and in particular relates to a closed-loop feedback control method of an automatic gain link of a focusing and leveling sensor with self-adaptive capability. Background technique [0003] The photolithography machine is an exposure device that transfers the pattern on the mask to the object to be processed (such as silicon wafer, etc.) in a certain proportion. see figure 1 , in the projection lithography machine, the exposure light beam illuminates the mask 18 engraved with the integrated circuit pattern, and the mask 18 is imaged on the silicon wafer 6 of the processing object through the projection objective ...

AI Technical Summary

Problems solved by technology

First of all, the customer needs to make a corresponding spot switching table according to the specific characteristics of focusing and leveling, as well as each type of silicon wafer and the different layers of a type of silicon wafer, and needs to input this information into the In the lithography machine, this not only requires a large number of process experiments, but also needs to input a large amount of work definition data content during the work process, which increases the cost and difficulty of using the entire lithography machine, and also reduces the cost of the lithography machine. The production efficiency of the machine; secondly, the use of the spot switching table will also complicate the scanning control and the processing of the focus and leveling data; thirdly, due to the deterioration of the flatness of the photoresist on different silicon wafers or different positions in the same silicon wafer The characteristics such as the degree of degradation and deterioration do not fully follow the pre-delineated geometric boundaries of the inner field, the interface field, and the outer field. The practice of uniformly delineating the reliability boundary for a class of silicon wafers or a certain layer of silicon wafers may lead to focusing Leveling uses originally unreliable information or discards originally reliable information, which increases exposure failure rate and scrap rate to a certain extent

[0007] For the overflow problem of electronic components in the focusing and leveling system based on photoelectric detection, the existing technology also adopts the method of firstly conducting process tests and measurements, and then manually inputting the corresponding automatic gain factor in the signal processing circuit, and its disadvantage is also in production. A large number of process tests are required in the process, and the operator also needs to input corresponding selection data, which makes the use of the entire lithography machine more difficult and the production efficiency is low

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